The present invention relates to an improved method for determining an endotoxin and an apparatus therefor.
An endotoxin, one kind of pyrogen, has been measured by a fever test using rabbits. However, the fever test using rabbits is being replaced by a test utilizing Limulus Amebocyte Lysate (LAL), derived from circulating blood cells of horseshoe crab, Limulus polyphemus, (Limulus test). Since a Limulus reaction is inhibited or promoted by substances present in a measurement system, a certain pre-treatment to remove the influence of substances must be done in many cases. Examples of pre-treatment include dilution, heating, perchloric acid treatment and the like. However, all of these pre-treatments are insufficient to provide endotoxin measurement in having acceptable specificity, sensitivity and quantitativeness. In order to solve these problems, the present inventors have already developed a method for determining an endotoxin using an endotoxin adsorbent (EP-A 350004).
In order to improve the operation properties of the above method, the present inventors have also proposed another method wherein an endotoxin is adsorbed on an adsorbent and a reaction of adsorbed endotoxin with a Limulus reagent is carried out in a centrifugal filtration apparatus (EP-A 456252).